Klinik und Poliklinik für Strahlentherapie und Radioonkologie

BACKGROUND: In advanced prostate cancer (APC), successful drug development as well as advances in imaging and molecular characterisation have resulted in multiple areas where there is lack of evidence or low level of evidence. The Advanced Prostate Cancer Consensus Conference (APCCC) 2017 addressed some of these topics. OBJECTIVE: To present the report of APCCC 2017. DESIGN, SETTING, AND PARTICIPANTS: Ten important areas of controversy in APC management were identified: high-risk localised and locally advanced prostate cancer; "oligometastatic" prostate cancer; castration-naïve and castration-resistant prostate cancer; the role of imaging in APC; osteoclast-targeted therapy; molecular characterisation of blood and tissue; genetic counselling/testing; side effects of systemic treatment(s); global access to prostate cancer drugs. A panel of 60 international prostate cancer experts developed the program and the consensus questions. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The panel voted publicly but anonymously on 150 predefined questions, which have been developed following a modified Delphi process. RESULTS AND LIMITATIONS: Voting is based on panellist opinion, and thus is not based on a standard literature review or meta-analysis. The outcomes of the voting had varying degrees of support, as reflected in the wording of this article, as well as in the detailed voting results recorded in Supplementary data. CONCLUSIONS: The presented expert voting results can be used for support in areas of management of men with APC where there is no high-level evidence, but individualised treatment decisions should as always be based on all of the data available, including disease extent and location, prior therapies regardless of type, host factors including comorbidities, as well as patient preferences, current and emerging evidence, and logistical and economic constraints. Inclusion of men with APC in clinical trials should be strongly encouraged. Importantly, APCCC 2017 again identified important areas in need of trials specifically designed to address them. PATIENT SUMMARY: The second Advanced Prostate Cancer Consensus Conference APCCC 2017 did provide a forum for discussion and debates on current treatment options for men with advanced prostate cancer. The aim of the conference is to bring the expertise of world experts to care givers around the world who see less patients with prostate cancer. The conference concluded with a discussion and voting of the expert panel on predefined consensus questions, targeting areas of primary clinical relevance. The results of these expert opinion votes are embedded in the clinical context of current treatment of men with advanced prostate cancer and provide a practical guide to clinicians to assist in the discussions with men with prostate cancer as part of a shared and multidisciplinary decision-making process.

BACKGROUND: Circulating tumour cells (CTCs) have shown prognostic relevance in metastatic breast, prostate, colon and pancreatic cancer. For further development of CTCs as a biomarker, we compared the performance of different protocols for CTC detection in murine breast cancer xenograft models (MDA-MB-231, MDA-MB-468 and KPL-4). Blood samples were taken from tumour bearing animals (20 to 200 mm2) and analysed for CTCs using 1. an epithelial marker based enrichment method (AdnaTest), 2. an antibody independent technique, targeting human gene transcripts (qualitative PCR), and 3. an antibody-independent approach, targeting human DNA-sequences (quantitative PCR). Further, gene expression changes associated with epithelial-to-mesenchymal transition (EMT) were determined with an EMT-specific PCR assay. METHODS: We used the commercially available Adna Test, RT-PCR on human housekeeping genes and a PCR on AluJ sequences to detect CTCs in xenografts models. Phenotypic changes in CTCs were tested with the commercially available "Human Epithelial to Mesenchymal Transition RT-Profiler PCR Array". RESULTS: Although the AdnaTest detects as few as 1 tumour cell in 1 ml of mouse blood spiking experiments, no CTCs were detectable with this approach in vivo despite visible metastasis formation. The presence of CTCs could, however, be demonstrated by PCR targeting human transcripts or DNA-sequences - without epithelial pre-enrichment. The failure of CTC detection by the AdnaTest resulted from downregulation of EpCAM, whereas mesenchymal markers like Twist and EGFR were upregulated on CTCs. Such a change in the expression profile during metastatic spread of tumour cells has already been reported and was linked to a biological program termed epithelial-mesenchymal transition (EMT). CONCLUSIONS: The use of EpCAM-based enrichment techniques leads to the failure to detect CTC populations that have undergone EMT. Our findings may explain clinical results where low CTC numbers have been reported even in patients with late metastatic cancers. These results are a starting point for the identification of new markers for detection or capture of CTCs, including the mesenchymal-like subpopulations.

Ionizing radiation can lead to a variety of deleterious effects in humans, most importantly to the induction of cancer. DNA double-strand breaks (DSBs) are among the most significant genetic lesions introduced by ionizing radiation that can initiate carcinogenesis. We have enumerated gamma-H2AX foci as a measure for DSBs in lymphocytes from individuals undergoing computed tomography examination of the thorax and/or the abdomen. The number of DSBs induced by computed tomography examination was found to depend linearly on the dose-length product, a radiodiagnostic unit that is proportional to both the local dose delivered and the length of the body exposed. Analysis of lymphocytes sampled up to 1 day postirradiation provided kinetics for the in vivo loss of gamma-H2AX foci that correlated with DSB repair. Interestingly, in contrast to results obtained in vitro, normal individuals repair DSBs to background levels. A patient who had previously shown severe side effects after radiotherapy displayed levels of gamma-H2AX foci at various sampling times postirradiation that were several times higher than those of normal individuals. Gamma-H2AX and pulsed-field gel electrophoresis analysis of fibroblasts obtained from this patient confirmed a substantial DSB repair defect. Additionally, these fibroblasts showed significant in vitro radiosensitivity. These data show that the in vivo induction and repair of DSBs can be assessed in individuals exposed to low radiation doses, adding a further dimension to DSB repair studies and providing the opportunity to identify repair-compromised individuals after diagnostic irradiation procedures.

OBJECTIVE: To evaluate the use of positron emission tomography using [(18)F]-fluorodeoxyglucose (FDG-PET) to assess the response to neoadjuvant radiotherapy and chemotherapy in patients with locally advanced esophageal cancer. SUMMARY BACKGROUND DATA: Imaging modalities, including endoscopy, endoscopic ultrasound, computed tomography, and magnetic resonance imaging, currently used to evaluate response to neoadjuvant treatment in esophageal cancer do not reliably differentiate between responders and nonresponders. METHODS: Twenty-seven patients with histopathologically proven squamous cell carcinoma of the esophagus, located at or above the tracheal bifurcation, underwent neoadjuvant therapy consisting of external-beam radiotherapy and 5-fluorouracil as a continuous infusion. FDG-PET was performed before and 3 weeks after the end of radiotherapy and chemotherapy (before surgery). Quantitative measurements of tumor FDG uptake were correlated with histopathologic response and patient survival. RESULTS: After neoadjuvant therapy, 24 patients underwent surgery. Histopathologic evaluation revealed less than 10% viable tumor cells in 13 patients (responders) and more than 10% viable tumor cells in 11 patients (nonresponders). In responders, FDG uptake decreased by 72% +/- 11%; in nonresponders, it decreased by only 42% +/- 22%. At a threshold of 52% decrease of FDG uptake compared with baseline, sensitivity to detect response was 100%, with a corresponding specificity of 55%. The positive and negative predictive values were 72% and 100%. Nonresponders to PET scanning had a significantly worse survival after resection than responders. CONCLUSION: FDG-PET is a valuable tool for the noninvasive assessment of histopathologic tumor response after neoadjuvant radiotherapy and chemotherapy.

BACKGROUND: Nonmelanoma carcinomas of the skin represent the most frequent cancers among the Caucasian population worldwide. They occur with high frequency in renal allograft recipient patients after prolonged immunosuppression. PURPOSE: We analyzed tumors obtained from both immunosuppressed and nonimmunosuppressed patients for human papillomavirus (HPV) DNA. METHODS: Twenty-nine specimens of nonmelanoma carcinomas of the skin were obtained from 19 renal allograft recipient patients; these included 20 specimens of squamous cell carcinoma (SCC) from 11 patients, five specimens of basal cell carcinoma (BCC) from four patients, and four specimens of carcinoma in situ (CIS) from four patients. Forty-one specimens of nonmelanoma carcinomas of the skin were obtained from 32 nonimmunosuppressed patients; these included 26 SCC specimens from 19 patients, 11 BCC specimens from nine patients, and four keratoacanthoma (benign epithelial tumor) specimens from four patients. A polymerase chain reaction method involving use of degenerate oligonucleotide primers, in which the conserved region of the open reading frame of the HPV L1 (major capsid protein) gene is amplified, was used to amplify total cellular DNA purified from individual tumors. The DNA of each specimen was subjected to 16 different amplification reactions; different primer combinations were used in order to increase the sensitivity and specificity of HPV detection. Resulting products were probed with a radioactively labeled, degenerate oligonucleotide. HPV-specific DNA was either sequenced directly after elution from the gel or amplified with semi-nested, degenerate primers, after which the products were cloned and sequenced. Sequences were compared with all known papillomavirus sequences. RESULTS: Thirteen (65%) of the 20 SCC specimens and three of the five BCC specimens from immunosuppressed (renal allograft recipient) patients contained identifiable HPV-related sequences, among them 13 putative novel HPV genomes. In addition, all other malignant tumor specimens from this patient group revealed faint signals upon amplification and hybridization; the origin of these signals has not been identified in the present study. In nonimmunosuppressed patients, eight (31%) of 26 SCC specimens and four (36%) of 11 BCC specimens contained sequences of HPV types. Two putative novel HPV sequences could be identified in this group. Faint signals of yet undetermined origin were observed in eight of the SCC specimens and in two of the BCC specimens. Two of four keratoacanthoma specimens contained sequences of known HPV type. (Keratoacanthoma is a nonmalignant lesion for which the natural history has not been defined.) The spectrum of HPV types in both groups of patients differed substantially. CONCLUSIONS: These data point to the frequent presence of HPV sequences in SCCs and BCCs of the skin. The etiologic relationship of these infections to the respective malignant tumors remains to be evaluated. IMPLICATIONS: The presence of HPV DNA in a large percentage of specimens of nonmelanoma carcinomas of the skin from immunosuppressed patients, as well as from nonimmmunosuppressed patients, renders a papillomavirus infection as a possible factor in the etiology of this disease.

BACKGROUND: Autoantibodies against synthetic peptides of beta-adrenergic receptors have been observed in human cardiomyopathy. However, it has never been shown that such antibodies really interact with native human beta-adrenergic receptors, nor has the clinical impact of such an interaction been investigated in larger groups of patients. METHODS AND RESULTS: We screened 104 patients with dilated or ischemic cardiomyopathy (NYHA functional classes II to IV) and 108 healthy subjects for IgG antibodies reacting with beta-receptor peptides. Such IgGs were further analyzed for binding and functional interactions with native recombinant human beta-adrenergic receptors. Antibodies reacting with synthetic receptor peptides were present in 51% of the patients. However, only a subgroup directed against the second extracellular receptor domain also recognized native human beta-adrenergic receptors situated in a cell membrane. All antibodies of this subgroup impaired receptor ligand binding and enhanced receptor-mediated signaling, which could be blocked by 5 micromol/L bisoprolol in vitro. Their prevalence was 1% in healthy subjects and 10% in ischemic cardiomyopathy, whereas it amounted to 26% in dilated cardiomyopathy and was associated with a significantly poorer left ventricular function. CONCLUSIONS: Our data show that activating autoantibodies against human beta-adrenergic receptors exist in approximately 25% of patients with dilated cardiomyopathy. Counteraction of such autoantibodies might contribute to the beneficial effects of beta-adrenergic receptor blockade in chronic heart failure.

A novel procedure is proposed to extract T(1), T(2), and relative spin density from the signal time course sampled with a series of TrueFISP images after spin inversion. Generally, the recovery of the magnetization during continuous TrueFISP imaging can be described in good approximation by a three parameter monoexponential function S(t) = S(stst)(1-INV exp(-t/T(*) (1)). This apparent relaxation time T(*) (1) <or= T(1) depends on the flip angle as well as on both T(1) and T(2). Here, it is shown that the ratio T(1)/T(2) can be directly extracted from the inversion factor INV, which describes the relation of the signal value extrapolated to t = 0 and the steady-state signal. Analytical expressions are given for the derivation of T(1), T(2), and relative spin density directly from the fit parameters. Phantom results show excellent agreement with single point reference measurements. In human volunteers T(1), T(2), and spin density maps in agreement with literature values were obtained.

AIM: The standard treatment for patients with clinically resectable rectal cancer is surgery. Postoperative radiochemotherapy (RCT) is recommended for advanced disease (pT3/4 or pN+). In recent years, encouraging results of pre-operative radiotherapy have been reported. This prospective randomized phase-III-trial (CAO/ARO/AIO-94) compares the efficacy of neoadjuvant RCT to standard postoperative RCT. We report on the design of the study and first results with regard to toxicity of RCT and postoperative morbidity. PATIENTS AND METHODS: Patients with locally advanced operable rectal cancer (uT3/4 or uN+, Mason CS III/IV) were randomly assigned to pre or postoperative RCT: A total dose of 50.4 Gy (single dose 1.8 Gy) was applied to the tumour and the pelvic lymph nodes. 5-FU (1000 mg/m2/d) was administered concomitantly in the 1th and 5th week of radiation as 120 h-continuous infusion. Four additional cycles of 5-FU-chemotherapy (500 mg/m2/d, i.v.-bolus) were applied. RCT was identical in both arms except for a small-volume boost of 5.4 Gy postoperatively. The time interval between RCT and surgery was 4-6 weeks in both arms. Techniques of surgery were standardized and included total mesorectal excision. Primary endpoints of the study are 5-year survival and local and distant control. Secondary endpoints include the rate of curative (R0) resection and sphincter saving procedures, toxicity of RCT, surgical complications and quality of life. RESULTS: As of July 2002, 805 patients were randomized from 26 participating institutions. Acute toxicity (WHO) of RCT was low, with less than 15% of patients experiencing grade 3 or higher toxicity: The principal toxicity was diarrhea, with 12% in the postoperative RCT-arm and 11% in the pre-operative RCT-arm having grade 3-, and 1% in either arm having grade 4-diarrhea. Erythema, nausea and leukopenia were the next common toxicities, with less than 3% of patients in either arm suffering grade 3 or greater leukopenia or nausea. Postoperative complication rates were similar in both arms, with 12% (postop. RCT) and 12% (pre-op. RCT) of patients, respectively, suffering from anastomotic leakage, 3% (postop. RCT) and 3% (pre-op. RCT) from postoperative bleeding, and 6% (postop. RCT) and 4% (pre-op. RCT) from delayed wound healing. CONCLUSION: The patient accrual to the trial is satisfactory. Neoadjuvant RCT is well tolerated and bears no higher risk for postoperative morbidity.

Bei diesem Dokument handelt es sich um die aktualisierte Fassung der 2006 erstmals erstellten S3-Leitlinie zum exokrinen Pankreaskarzinom.

Abstract An efficient method for the determination of the ploidy level is described, based on a measurement of the DNA content of interphase nuclei by flow cytometry. Both individual plants as well as plant populations can be used to obtain the desired DNA‐histograms Compared to conventional chromosome counting flow cytometry turned out to be highly competitive in terms of simplicity, accuracy, and costs.

BACKGROUND: Chylothorax arises when lymphatic fluid (chyle) accumulates in the pleural cavity because of leakage from lymphatic vessels. It is most commonly seen after thoracic surgery (in 0.5% to 1% of cases) and in association with tumors. No prospective or randomized trials have yet been performed to evaluate the available treatment options. METHOD: This review is based on a selective search of the PubMed database for pertinent publications from the years 1995 to 2013. Emphasis was laid on articles that enabled a comparative assessment of treatment options. RESULTS: Initial conservative treatment (e.g., parenteral nutrition or a special diet) succeeds in 20% to 80% of cases. When such treatment fails, the standard approach up to the present has been to treat surgically, e.g., with ligation of the thoracic duct, pleurodesis, or a pleuroperitoneal shunt. The success rates of such procedures have ranged from 25% to 95%. Most of the patients undergoing such procedures are severely ill; complication rates as high as 38% have been reported, with mortality as high as 25%. In more recent publications, however, morbidity and mortality were lower. Interventional radiological treatments, such as percutaneous thoracic duct embolization or the percutaneous destruction of lymphatic vessels, succeed in about 70% of cases and lead to healing in up to 80% of cases, even after unsuccessful surgery. The complication rate of percutaneous methods is roughly 3%. CONCLUSION: Interventional radiological procedures have now taken their place alongside conservative treatment and surgery in the management of chylothorax, although they are currently available in only a small number of centers.

PURPOSE: Maintenance of telomeres through reactivation of telomerase is a prerequisite for tumors to preserve their ability to proliferate. The purpose of this study was to evaluate telomere length and human telomerase reverse transcriptase (hTERT) expression as markers for progression and prognosis of colorectal carcinoma. PATIENTS AND METHODS: Telomere length and hTERT expression were analyzed in matched cancer and adjacent noncancer mucosa samples from 57 patients with R0-resected colorectal carcinoma. The median follow-up time was 76 months. RESULTS: Telomere length and hTERT expression correlated significantly in cancer tissues and adjacent mucosa samples (r = 0.52, P <.001; and r = 0.54, P <.001, respectively). Overall, cancer tissue had shorter telomeres than adjacent mucosa (P <.001). Only in noncancer tissue did telomere length decrease with age (r = 0.36; P <.01). Telomere length in cancer tissue was significantly correlated with tumor stage (P <.01), with longer telomeres in advanced tumors. Patients with ratios of telomere length in cancer to noncancer tissue greater than 0.90 had a significantly poorer overall survival compared with patients with smaller telomere length ratios (P <.002). In multivariate analysis, the telomere length ratio proved to be of independent prognostic value (P <.03). CONCLUSION: Telomeres in colorectal carcinoma tissue were significantly shorter compared with adjacent normal mucosa as an indication for extensive cell proliferation. The correlation with tumor stage and patient survival suggest that hTERT-mediated telomere stabilization may be critical for progression and prognosis of colorectal carcinoma.

We report on the first irradiation of in vitro tumour cells with laser-accelerated proton pulses showing dose-dependent biological damage. This experiment, paving the way for future radiobiological studies with laser-accelerated protons, demonstrates the simultaneous availability of all the components indispensable for systematic radiobiological studies: a laser–plasma accelerator providing proton spectra with maximum energy exceeding 15 MeV and applicable doses of a few Gy within a few minutes; a beam transport and filtering system; an in-air irradiation site; and a dosimetry system providing both online dose monitoring and absolute dose information applied to the cell sample and the full infrastructure for analysing radiation-induced damage in cells.

AIMS: Preliminary reports indicate that sirolimus-eluting stents reduce the risk of restenosis after percutaneous infrapopliteal artery revascularization. We conducted a prospective, randomized, multi-centre, double-blind trial comparing a polymer-free sirolimus-eluting stent with a placebo-coated bare-metal stent in patients with either intermittent claudication or critical limb ischaemia who had a de-novo lesion in an infrapopliteal artery. METHODS AND RESULTS: 161 patients were included in this trial. The mean target lesion length was 31 ± 9 mm. The main study endpoint was the 1-year primary patency rate, defined as freedom from in-stent-restenosis (luminal narrowing of ≥50%) detected with duplex ultrasound if not appropriate with angiography. Secondary endpoints included the 6-month primary patency rate, secondary patency rate, and changes in Rutherford-Becker classification after 1 year. Twenty-five (15.5%) patients died during the follow-up period. One hundred and twenty-five patients reached the 1-year examinations. The 1-year primary patency rate was significantly higher in the sirolimus-eluting stent group (80.6%) than in the bare-metal stent group (55.6%, P= 0.004), and the 1-year secondary patency rates were 91.9 and 71.4% (P= 0.005), respectively. The median (interquartile range) change in Rutherford-Becker classification after 1 year was -2 (-3 to -1) in the sirolimus-eluting stent group and -1 (-2 to 0) in the bare-metal stent group, respectively (P= 0.004). CONCLUSION: Mid-term patency rates of focal infrapopliteal lesions are substantially improved with sirolimus-eluting stent compared with bare-metal stent. Corresponding to the technical results, the changes in Rutherford-Becker classification reveal a significant advantage for the sirolimus-eluting stent.

The major prognostic indicator in patients with breast cancer is the presence of metastases in axillary lymph nodes. The authors developed a mathematical model, based on 1446 complete axillary dissections performed in Milan between 1983 and 1986, and determined the following: (1) the sample size from Level I necessary for a 90% certainty degree of N0 axillary status; (2) the probability of residual tumor in the axilla after axillary sampling from Level I; and (3) the maximum number of involved axillary nodes in Levels I, II, and III to be expected (90% certainty) after sampling from Level I. Thus, this model permitted the determination of the cutoff level for a true N0 axillary status when only a few nodes are sampled from Level I. The cutoff level for a T1 primary tumor is ten axillary nodes removed and found uninvolved. Also, this model provides guidance in managing possible residual tumor after an incomplete axillary dissection. This information is important in indicating adjuvant axillary radiation therapy and chemotherapy or hormone therapy.

Dieses Dokument wurde zum persnlichen Gebrauch heruntergeladen. Vervielfltigung nur mit Zustimmung des Verlages.

Stereotactic radiotherapy with its forms of intracranial stereotactic radiosurgery (SRS), intracranial fractionated stereotactic radiotherapy (FSRT) and stereotactic body radiotherapy (SBRT) is today a guideline-recommended treatment for malignant or benign tumors as well as neurological or vascular functional disorders. The working groups for radiosurgery and stereotactic radiotherapy of the German Society for Radiation Oncology (DEGRO) and for physics and technology in stereotactic radiotherapy of the German Society for Medical Physics (DGMP) have established a consensus statement about the definition and minimal quality requirements for stereotactic radiotherapy to achieve best clinical outcome and treatment quality in the implementation into routine clinical practice.

BACKGROUND: Ongoing changes in cancer care cause an increase in the complexity of cases which is characterized by modern treatment techniques and a higher demand for patient information about the underlying disease and therapeutic options. At the same time, the restructuring of health services and reduced funding have led to the downsizing of hospital care services. These trends strongly influence the workplace environment and are a potential source of stress and burnout among professionals working in radiotherapy. METHODS AND PATIENTS: A postal survey was sent to members of the workgroup "Quality of Life" which is part of DEGRO (German Society for Radiooncology). Thus far, 11 departments have answered the survey. 406 (76.1%) out of 534 cancer care workers (23% physicians, 35% radiographers, 31% nurses, 11% physicists) from 8 university hospitals and 3 general hospitals completed the FBAS form (Stress Questionnaire of Physicians and Nurses; 42 items, 7 scales), and a self-designed questionnaire regarding work situation and one question on global job satisfaction. Furthermore, the participants could make voluntary suggestions about how to improve their situation. RESULTS: Nurses and physicians showed the highest level of job stress (total score 2.2 and 2.1). The greatest source of job stress (physicians, nurses and radiographers) stemmed from structural conditions (e.g. underpayment, ringing of the telephone) a "stress by compassion" (e.g. "long suffering of patients", "patients will be kept alive using all available resources against the conviction of staff"). In multivariate analyses professional group (p < 0.001), working night shifts (p = 0.001), age group (p = 0.012) and free time compensation (p = 0.024) gained significance for total FBAS score. Global job satisfaction was 4.1 on a 9-point scale (from 1 - very satisfied to 9 - not satisfied). Comparing the total stress scores of the hospitals and job groups we found significant differences in nurses (p = 0.005) and physicists (p = 0.042) and a borderline significance in physicians (p = 0.052).In multivariate analyses "professional group" (p = 0.006) and "vocational experience" (p = 0.036) were associated with job satisfaction (cancer care workers with < 2 years of vocational experience having a higher global job satisfaction). The total FBAS score correlated with job satisfaction (Spearman-Rho = 0.40; p < 0.001). CONCLUSION: Current workplace environments have a negative impact on stress levels and the satisfaction of radiotherapy staff. Identification and removal of the above-mentioned critical points requires various changes which should lead to the reduction of stress.

This abridged version is based on an interdisciplinary guideline which corresponds to development stage 3 (S3) of guidelines according to the classification of the Association of the Scientific Medical Societies in Germany (AWMF). The guideline development process is characterized by the combination of formal evidence-search, formal consensus, logic (algorithms), decision and outcome analysis, and interdisciplinary development with the cooperation of 15 German and Austrian medical societies. [Table 1] shows the relationship between levels of evidence, consensus, and resulting recommendation grades of the recommendations of this guideline. The recommendation grades A – D are added to the recommendations in the abridged version. For the evidence levels, see the full version [1].

UNLABELLED: (18)F-FDG PET/CT is effective in the assessment of therapy response. Changes in glucose uptake or tumor size are used as a measure. Tumor heterogeneity was found to be a promising predictive and prognostic factor. We investigated textural parameters for their predictive and prognostic capability in patients with rectal cancer using histopathology as the gold standard. In addition, a comparison to clinical outcome was performed. METHODS: Twenty-seven patients with rectal cancer underwent (18)F-FDG PET/CT before, 2 wk after the start, and 4 wk after the completion of neoadjuvant chemoradiotherapy. In all PET/CT scans, conventional parameters (tumor volume, diameter, maximum and mean standardized uptake values, and total lesion glycolysis [TLG]) and textural parameters (coefficient of variation [COV], skewness, and kurtosis) were determined to assess tumor heterogeneity. Values on pretherapeutic PET/CT as well as changes early in the course of therapy and after therapy were compared with histopathologic response. In addition, the prognostic value was assessed by correlation with time to progression and survival time. RESULTS: The COV showed a statistically significant capability to assess histopathologic response early in therapy (sensitivity, 68%; specificity, 88%) and after therapy (79% and 88%, respectively). Thereby, the COV had a higher area under the curve in receiver-operating-characteristic analysis than did any analyzed conventional parameter for early and late response assessment. The COV showed a statistically significant capability to evaluate disease progression and to predict survival, although the latter was not statistically significant. CONCLUSION: Tumor heterogeneity assessed by the COV, being superior to the investigated conventional parameters, is an important predictive factor in patients with rectal cancer. Furthermore, it can provide prognostic information. Therefore, its application is an important step for personalized treatment of rectal cancer.